Dr. William Bayer, MD

Dr. William Bayer, MD

Endocrinology, Diabetes & Metabolism  |  
Male  |  
56 y/o
24 reviews

Accepting new patients

Accepted insurance

  • Aetna
  • Blue Cross Blue Shield of Illinois
  • Cigna
  • Cigna-HealthSpring
  • CorVel
  • Coventry Health Care
  • First Health (Coventry Health Care)
  • HealthLink
  • HFN
  • Humana
  • LifeSynch
  • Medicaid
  • MultiPlan
  • UniCare

Learn about this doctor

Care Philosophy

Dr. Bayer specializes in Endocrinology, Diabetes & Metabolism and practices in Carol Stream, IL. He practices at 2 locations.

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Dr. Bayer's Experience

Experience Match

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Board Certifications

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Conditions Treated

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Procedures Performed

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Background Check

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Awards & Recognition

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Languages Spoken

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Memberships & Professional Affiliations

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Visiting Dr. Bayer

Dr. Bayer accepts 16 insurance carriers

Affiliated Hospitals

Hospital Quality
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Dr. Bayer's Reviews

Likelihood of recommending Dr. Bayer to family and friends
based on 24 total surveys (10 with reviews)
Dr. Bayer's Performance
  • Trustworthiness
  • Explains condition(s) well
  • Answers Questions
  • Time well spent
Office & Staff Performance
  • Scheduling
  • Office environment
  • Staff friendliness
  • Average wait time
    16 to 30 minutes
Patient Reviews (10)
in St. Charles IL. |
Dr. Bayer is a Diabetic Endocrinologist that I have complete trust in has really turned my A1C Goal/Goals to the Positive. He is very knowledgeable in his field and he always spends appropriate time w/patient/patients. I will be 62 in December and have been battling Diabetes since 1999/2000. He has also been a big influence on how I feel about my condition-always Positive. He has my Thanks! Bryan Compton
Do not take the bad reviews seriously! Dr. Bayeris amazing & caring! So, if you need a really good doctor that cares about your health & does not set a timer when you walk in, he is your answer to getting your health back on track! I came to him when there was no one else. He cared & I am now on my way to not only answers but resolutions. He has a good heart & is a briliant doctor! If you are serious about working on your health & learning how to be healthier but need a coach; he is for you!
Hoffman Estates, IL |
Dr Bayer is a no-nonsense doctor that is very knowledgable and thoruough. I have gone to him for many years before a car accident and am now able to see him again. I could not find his phone number so I looked it up. As I read the reveiws that were positive, I could relate. As I read the negative reviews I wondered what could have gone wrong. I made my appointment a little concerned. Well, I can only say that Dr. Bayer is still the caring wonderful doctor that I remember.
in Aurora, IL |
He needs to retire. He's clearly mad at everything, he was 30 minutes late to an 8:00 am meeting and told me out of the gate he already didn't know what to do. He took no time to listen and understand. he's terrible, go somewhere else
Wheaton, IL |
One of the worst doctors I have ever seen. Rude, disrespectful, and just plain mean. He doesn't care about patients and this was shown by his horrible bedside manner. He needs training on how to be nice to people.
Chicago, IL |
Dr. Bayer is so nice. He listens and is excited when he sees me progressing in my health. Worked consistently to get my thyroid medication to the appropriate level.
IL |
Rude bedside manner, rushes through, and was annoyed when I had to mention multiple health issues. He really seems to hate his job. Probably competent with thyroid issues but just too rude and unhappy!
Aurora, IL |
Dr Bayer acted like a robot. Dr Bayer made eye contact 5 seconds during the entire appointment. He spent all his time filling out forms on his computer instead of listening to any concerns I had. His bedside manner is horrible, he is extremely unwilling to entertain other professional opinions. He was very concerned about if insurance will cover instead of the care of the patient, save yourself the frustration find a different doctor who cares about your health & issues.
in Aurora, IL |
Everything I heard about Dr. Bayer from other Doctors and the general public is true. He will take the extra mile on getting to the root of your issues. I felt comfortable with his personality and concern for my health and well being.
Wouldn't recommend.
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More Endocrinology, Diabetes & Metabolism Specialists like Dr. Bayer at Northwestern Medicine Regional Medical Group

Dr. Bayer's experience matches your search based on the following criteria:

  •  Based on total number of patients treated over the last 12 months
  •  Specializes in Endocrinology, Diabetes & Metabolism
  •  Board certified in Diabetes, Metabolism & Endocrinology and Internal Medicine
  •  No malpractice claims found
  •  No sanctions found
  •  No board actions found

Awards & Recognition

  • Awards & Honors
    • Healthgrades Honor Roll
    What is a recognized doctor
  • Media & Publications

    Dr. Bayer has no media or publications listed.

Background Check

  • 0
    Malpractice Claims

    No malpractice history found for Illinois.

    What is medical malpractice
  • 0

    No sanctions history found for the years that Healthgrades collects data.

    What is a sanction or disciplinary action
  • 0
    Board Actions

    No board actions found for the years that Healthgrades collects data.

    What are board actions

Board Certifications

Why It Matters: Dr. Bayer's Board Certifications

Board certification should be one of your top considerations when choosing a doctor. Board certification is an official recognition given to doctors who have met specific requirements set by national medical specialty boards in the... More

  • Diabetes, Metabolism & Endocrinology
  • Internal Medicine

Conditions Treated

  • Abnormal Thyroid
  • Acromegaly and Gigantism
  • Adrenal Gland Diseases
  • Adrenal Incidentaloma
  • Adrenal Insufficiency
  • Autoimmune Diseases
  • Autoimmune Thyroid Diseases
  • Benign Tumor
  • Bone Disorders
  • Breast Diseases
  • Calcium Metabolism Disorders
  • Cancer
  • Congenital Adrenal Hyperplasia (CAH)
  • Cushing's Syndrome
  • Diabetes Insipidus
  • Diabetes Type 1
  • Diabetes Type 2
  • Diabetes With Renal Manifestations
  • Goiter
  • Gynecomastia
  • Hashimoto's Disease
  • Hypercalcemia
  • Hyperlipidemia
  • Hyperparathyroidism
  • Hyperthyroidism
  • Hypokalemia
  • Hypoparathyroidism
  • Hypopituitarism
  • Hypothyroidism
  • Kidney Disease
  • Lipid Disorders
  • Malaise and Fatigue
  • Menstrual Disorders (incl. Dysmenorrhea)
  • Multiple Endocrine Neoplasia
  • Obesity
  • Osteopenia
  • Osteoporosis
  • Parathyroid (Gland) Disease
  • Phosphorus Metabolism Disorders
  • Polycystic Ovarian Syndrome
  • Symptomatic Menopause
  • Testicular Dysfunction
  • Thyroid Cancer
  • Thyroid Cyst
  • Thyroid Disease
  • Thyroiditis
  • Vitamin D Deficiency


  • Medical School
    Loyola University of Chicago / Stritch School of Medicine

    Graduated in 1986

  • Internship Hospital
    Loyola University Medical Center
  • Residency Hospital
    Loyola University Medical Center
  • Fellowship Hospital
    Loyola University Medical Center

Languages Spoken

  • English

Memberships &
Professional Affiliations

Dr. Bayer does not have any memberships or affiliations listed. If you are Dr. Bayer and would like to add memberships or affiliations, please update your free profile.


  • Endocrinology, Diabetes & Metabolism

Procedures Performed

  • Continuous Glucose Monitoring
  • Diabetes Counseling